generics.deprecatedInterfaceDefault

This error is reported by phpstan/phpstan-deprecation-rules.

Code example

<?php declare(strict_types = 1);

/** @deprecated Use NewInterface instead */
interface OldInterface
{
}

/**
 * @template T = OldInterface
 */
class Container
{
}

Why is it reported?

A @template tag uses a deprecated interface as its default type. The interface referenced in the default value of the template parameter has been marked with the @deprecated PHPDoc tag, indicating it is scheduled for removal or replacement. When the deprecated interface is removed, the template default will become invalid.

How to fix it

Replace the deprecated interface with its recommended replacement in the template default:

 <?php declare(strict_types = 1);

 /**
- * @template T = OldInterface
+ * @template T = NewInterface
  */
 class Container
 {
 }